1. Field
The present disclosure relates to techniques for communicating optical signals. More specifically, the present disclosure relates to a multiple-wavelength laser that includes a multiple-mode laser and ring-resonator filters.
2. Related Art
Silicon photonics is a promising technology that can provide large communication bandwidth, low latency and low power consumption for inter- and intra-chip interconnects. In the last few years, significant progress has been made in developing low-cost components for use in inter- and intra-chip silicon-photonic interconnects, including: high-bandwidth efficient silicon modulators, low-loss optical waveguides, wavelength-division-multiplexing (WDM) components, and high-speed CMOS optical-waveguide photo-detectors. However, a suitable low-cost WDM laser source remains a challenge and poses an obstacle to implementing WDM silicon-photonic links.
In particular, existing WDM lasers (such as those used to transmit optical signals in WDM telecommunications systems) are usually very expensive and are typically single-wavelength sources. Because future WDM silicon-photonic links are expected to include thousands of optical channels (or more), the total cost of these WDM laser sources is likely to be prohibitive.
In addition, a variety of other techniques have been investigated to make a multiple-wavelength laser source. These approaches include an electrically pumped distributed-feedback laser array based on the hybrid bonding of III-V materials onto silicon. However, the yield and scaling of these laser arrays may make it difficult to obtain a low-cost laser source. In an alternative approach, a single broad-spectrum light emitter is used (such as: a superluminescent diode, a broadband laser, and a mode-locked comb laser) instead of the distributed-feedback laser array. Nonetheless, because of their size, cost and power consumption, the resulting laser sources also have not achieved a low-cost solution for use in a WDM silicon-photonic link. Furthermore, while a comb laser based on quantum dots has recently shown promise for transmitting wavelengths in the O band (1260-1360 nm), this laser source is not thought to be suitable for use in a WDM silicon-photonic link because of the limited availability of associated modulators and detectors.
Hence, what is needed is a multiple-wavelength laser source without the above-described problems.